Network Services

Network Services

Introduction:

In this blog post, I have worked with other members of a group to explain how different network services operate as well as providing its advantages and limitations for each.  I worked with: Connor P, Sami, H, Liam B, and Ben C. The network services I will be talking about are:

• Packet Switched
• ISDN (Integrated Services Digital Network)
• ADSL Broadband (Asymmetric Digital Subscriber Line)
• WAP (Wireless Access Protocol).

Packet Switched:

Packet switches is a mechanism which sends network traffic in small manageable data units across the system. When you would like to send a file across to somebody else, the file breaks down into smaller sizes like 2MB for example and sends it across the internet in manageable chunks for it to rebuild itself at the end to display the following information.

The benefits of packet switches is that it only functions when there is a group of routers or WAN switches all interconnected, this is reliable because if one line of the branch fails then the data you would like to send (packet switches) will redirect to a different route line. You would use packet switches to direct traffic via a variety of routes such as through a mesh topology which is efficient in speed.

Furthermore, big companies with lots of employees would use this as it is much better than having cables due to the amount of cost and space it would require, therefore if they have many customers it means it is easy for it to be expanded.

However, the limitations for this is the time it requires for the data packages to be put back together as it is broken up in the first place and is not ideal for emergencies. Furthermore, it usually splits into packets of 600 bytes (60k approx.) so if a file is 512 bytes, it will require two packets doubling the time needed. This links to how some packets may not reach its destination and end up lost within the connection lines of mesh, slowing down every other packet.

Another limitation is if the main cloud fails down the whole mesh topology will follow.

Figure 1: Packet Switching

ISDN:

ISDN stands for integrated services digital network. It is an old circuit switched system for simultaneous digital transmission of voice, video, data and other network services (it is still in use for some places but technology has advanced and grown out of it slightly). ISDN was the first solution to transfer data and bypass the limitations set by the public telephone system in 1980’s.

The benefits of ISDN are that it can hold multiple connections by having separate channels for data. This gives it the capability to send voice and data simultaneously. It can also be used for ‘other signals’ by other organisations for different purposes.

Another benefit of ISDN network line is that it could be provided in two different ways. The first way is BRI (basic rate interface) and the second way is PRI (primary rate interface). BRI is for smaller businesses and smaller remote sites whereas PRI is for larger businesses, communities and organisations. This is because BRI can have two channels of approximately 60kb, each for voice and data communication signals. On the other hand, PRI can have 30B channels of 64K, allowing up to “30 voice lines” which are suitable for business purposes, (Anderson et al, 2011).

In addition to this, nowadays the modern ISDN connections are considered faster than traditional dial up connections because more development and research has been invested.

The limitations are that ISDN can be very costly because it requires specialised digital devices.  This network service would be used for connections in remote sites, or for customers such as a small business or home users.

Additionally, a limitation is the resources you send outside to the other networks will not be permanently available to other internet users; this is because ISDN functions in a way where you send video, voice, and data that cannot be retrievable afterwards.

Lastly, the last limitation of ISDN would be that modern ADLS (asymmetric digital subscriber line ) connections can transfer a lot more data in one go and are cheaper to maintain, putting ISDN below it as it has “no balance or symmetry”, (Anderson et al,  2011).

Figure 2: ISDN

ADSL Broadband:

Broadband, (referred to asymmetric digital subscriber line) has high speed for data transmission in which a single line or cable is capable of carrying large amounts of data at once. The most common form of broadband connections is cabled modems which provide a continuous connection to homes and businesses.

The benefits of broadband are that it is considerably faster than its predecessor baseband with technological advancements. Furthermore, another benefit is that it is easy to set up nowadays as technology has advanced to the stage where the entire physical network infrastructure is all built into one ‘hub’ – making it easier to handle for people with no prior knowledge of the communication devices. The third benefit is that different service providers now offer different packages making it easy to find the right one for you for the right purpose such as if it was purchased for a business or if it was purchased for residential purposes.

One limitation of broadband would be if you have two systems connected to the broadband but one is further away and one is nearer, the connection strength is prioritised towards the nearer system. This is because it doesn’t include a switch to regulate signal strength to all systems. Another limitation would be that the advertised download and upload speeds are rarely what they’re advertised to be. This means that you could be paying £100 a month for a 100MB/s speed when realistically you’re only getting 10MB/s (the density of area and other interference can be a role).

Lastly, ADSL Broadband is not well suited for all internet applications. This is because the ADSL "pipeline" to send data is quite small. Internet applications such as websites and VPN (Virtual Private Networking) are not well suited for ADSL Broadband as the way data is transmitted is different than usual. It may also be improved only if it has fibre optic cables rather than copper wires as then it travels faster.

Figure 3: Broadband

WAP – Wireless Access Protocol:

Wireless access protocol is a specification that allows users to access information and sends data with DTE (data terminal equipments) which are hand held only, such as a smartphone, communicator, or a mobile phone. To have the internet and display the webpage of a specific website that uses HTTP, the hand held device (smartphone) requests data through the internet to the HTTP server. At the server, it will return the requested data and resend it to the WAP server gateway (gateway connects two different networks) where this server will receive, process, and respond. The WAP server will then transmit the data back through the internet to the assigned device it requested from - allowing it to view the webpage it desired, (see figure 4). Overall WAP is a network service/structure that delivers, receives and transmits data across networks for emails, chats, and the internet to hand held devices.

The benefits of wireless access protocol are that improvements and advancements are being designed as time progresses, such as the upgrade from 3G to 4G – increasing the overall internet speed of how fast data transfers massively. Another benefit is the convenience of this network service for mobiles, this is because it copes well with small amounts of data such as for emails and text messages.

The limitations of wireless access protocol is the speed of the WAP system as it can be slow in general, taking some time to load up a page possibly due to other interference and by users in the same network. This limitation links with the first one; the speed and storage space of the device is a factor because it is also not suitable for large amounts of data such as large files alike animations as the bandwidth is incredibly huge, making it inconvenient and not recommended as a result. The third limitation to WAP is the cost of the set up as well as its maintenance cost because the design and creation of a mobile network has to live up to its expectations of many users – for example, a user will only get the amount of usage they paid for 3G whereas 4G is a slightly increased amount, this means that the market and businesses limit the amount they give. As mentioned about network service providers, WAP such as 3G and 4G are still used because it is convenient and is an easy method of internet access and communications in public such as phone calls. However as technology advances, 3G will be less likely to be used as 4G progress its way up due to being a successor of 3G.

Figure 4: Wireless Access Protocol

Harvard Referencing: (In order of reference)
- Anderson, K. Atkinson-Beaumont, D.Kaye, A. Lawson, J. McGill, R. Phillips, J and Richardson, D. 2011. Information Technology Level 3 Book 1 BTEC National. Harlow: Pearson Education Limited. P.304.
- teach-ict, n.d. Packet Switching. [Online] Available at: <http://www.teach-ict.com/technology_explained/packet_switching/packet_switching.html> [Accessed 16 January 2015].
- Access Points – Compnetworking.about.com, 2015. WAP Information [online] Available at: <http://compnetworking.about.com/cs/wireless/g/bldef_ap.html> [Accessed 01/2015]
(Conceptdraw.com, 2014)
- Access Points – Conceptdraw.com, 2014. WAP [online] Available at: <http://www.conceptdraw.com/examples/access-points> [Accessed 01/2015]
- Figure 1: webclasses, n.d. Packet Switch Diagram. [Online] Available at: <http://www.webclasses.net/3ComU/intro/units/media/figures/unit04/PacketSwitched.gif> [Accessed 16 January 2015].
- Figure 2: mynetfone, n.d. ISDN Diagram. [Online] Available at: <https://www.mynetfone.com.au/media/images/diagrams/QuadroISDN_diagram.jpg> [Accessed 16 January 2015].
- Figure 3: aitelephone, n.d. Broadband Diagram. [Online] Available at: <http://www.aitelephone.com/broadband-phone-diagram.gif> [Accessed 16 January 2015].
- Figure 4: althos, n.d. WAP Server Operation. [Online] Available at: <http://www.althos.com/sample_diagrams/ag_WML_WAP_Server_Operation_low_res.jpg> [Accessed 18 January 2015].

Bibliography: (In order of alphabet):
- orbit-computer-solutions, n.d. Wireless Routers. [Online] Available at: <http://orbit-computer-solutions.com/Wireless-Routers.php> [Accessed 16 January 2015].
- wcape.school, n.d. ISDN. [Online] Available at: <http://www.wcape.school.za/handbook/isdn.htm> [Accessed 16 January 2015].
- learning.ericsson, 2002. WAP. [Online] Available at: <http://learning.ericsson.net/mlearning2/project_one/wap_article.html> [Accessed 18 January 2015].
- wirelessdictionary, 2009. Wireless Access Protocol – WAP [Online] Available at: <http://www.wirelessdictionary.com/wireless_dictionary_WAP_definition.html> [Accessed 18 January 2015].